Most of the detectors use CAEN HV crates for their HV systems. The following models of CAEN crates are used: SY127, SY403, SY527 and SY1527. While for the latter, the slow control is done using CAEN OPC server, with Ethernet connection to the crate, in the case of all the other older models SLiC + DIM packages are used. SLiCs run either on VME processor or PC Linux platforms. The system is split in 5 CAENet buses.

    Straw and Silicon detectors use ISEG HV modules. These are controlled using a COMPASS-made SLiC, compiled as OPC Server, running on Windows 2000 platform. There are 2 CANbus branches in the system, one for each detector.

    More details on the ISEG for Straws implementation, and on the ISEG for Silicon implementation.

    Other detectors use home-made HV power supplies, which are not integrated in the DCS. In the case of ECal2 an alarm system was installed, to provide signal to DCS in case the HV switches off (using an ELMB analogue channel).

    Straw, RICH and SciFi detectors use Wiener LV power supplies. These will be integrated in the DCS during 2004 Run, using the Wiener OPC Server. The system will be split in 2 CANbus branches, one for Straws, and another to RICH, in a first stage. Later, these are to be merged in a single CANbus.

    Other detectors use home-made LV power-supplies. In the case of MWPC, MW1, MW2 and W45 these are monitored using ELMB analogue channels. The system is distributed per more than 10 ELMBs, in 2 separate CANbus branches.

    The Experiment uses Wiener fan-trays for the VME 9U crates. These are controlled in the DCS using a SLiC (running on Windows platform) + DIM. The connection is done using one CANbus into a Kvaser PCI-CAN Q card interface port.

    Most of the detectors' gas systems are controlled using 3 PLCs. There is monitoring of the status of the PLCs and compressors, as well as gas fluxes and mixtures, in PVSS via an OPC Server. The software for the PLCs is by Schneider Automation, while the OPC Server used is Modicom Telemechanique. Connection uses a CANbus into one port of a Kvaser PCI-CAN Q card.

   Details on the design of the gas systems for COMPASS (PLC2: RICH, MWPC, STRAWs) can be found here.

    The monitoring of slowly varying parameters like temperatures, humidities and atmospheric pressure, as well as other parameters like magnetic fields (measurement using Hall probes), and LV power supplies and VME power supplies, is done using ELMB ADC channels.

    Generic information about the ELMBs.

    Description of the ELMB system in COMPASS for the 2004 Run period.

   Racks cooling system (for the electronics racks and RICH detector).

   2 UPS units are connected to the main DCS computers in the Experiment: pccompass04, pccompass03 and na58pc014. They allow for the correct shutdown of PVSS in case of a sudden power cut, preventing corruption of PVSS databases.

   Technical details on the UPS's installed.